I have an Altos and really have not used it as much as I felt I would or that would warrant the expenditure.
Ironically, though, just this morning I determined another use for it. I love to make disappearing 4patch pinwheels...however, I hate to manually "turn" the fabric to cut it. I have a small cutting mat on a "lazy Susan" turn table, but it will not accommodate the large blocks I wanted to cut. I realized I could set my Altos on a turntable that I had in my cabinet for spices, and I did not have to move the fabric...just turn the Altos. That way I can cut up to 17" blocks. WooHoo!
I do "stablize" the Altos with my leg when cutting so that it will not turn and press down just a little to get a firm hold on my ruler...but I do not use the "T" shaped cutting edge that came with the Altos.
All in all, I would not buy it again. It takes up a lot of room, and I find I can cut just as fast without it. I'm sure there are some that it is their "best friend." But for me I think I would rather invest the money in thread. Just my 2 cents.